1. Field of the invention
The present invention relates to an electromagnetic relay, and more particularly to a low profile miniature electromagnetic relay having a base with an integrally molded enclosure for receiving therein an electromagnet and insulatively separating the same from a contact assembly mounted on the base outwardly of the enclosure.
2. Description of the prior art Electromagnetic relays, particularly relays requiring a higher contact rating within a small-sized casing are known to have a partition wall dividing the interior of a relay casing into two spaces, one for mounting an electromagnet and the other for a contact assembly. The relay construction having the above partition for separating the electromagnet from the contact assembly becomes more essential for designing a miniature relay in which components are dense-packed with a maximum insulation resistance between the electromagnet and the contact assembly. Prior relays having the above partition are disclosed, for example, in U.S. Pat. Nos. 4,101,856, 4,302,742, and 4,339,735, in all of which the partition extends along the length of the electromagnet for separation thereof from the contact assembly. However, all the partitions employed in each prior art relay must have a slot or opening within its length for passing therethrough a card or like actuating member which operatively connects the electromagnet to the contact assembly in order to actuate the switching operation of the contact assembly in response to the energization of the electromagnet. Unfortunately, due to the slot or opening formed in the partition, the partition fails to achieve complete insulation between the contact assembly and the electromagnet within the entire length of the electromagnet, and therefore the slot or opening is likely to form between the electromagnet and the contact assembly a shortcut leakage path through which a possible arcing originating from the contact assembly may extend to and damage the electromagnet. With the partition of the prior relays, therefore, the electrical insulation is interrupted at a portion of the partition so as to considerably reduce the effectiveness of the partition and only provide an unsatisfactory insulation effect, which is a hindrance to designing a miniature relay having a high contact rating in which magnetic and electric components are required to be dense-packed at a maximum insulation resistance.
One solution to the above problems is proposed in U.S. patent application Ser. No. 800,393 filed on Nov. 21, 1985 assigned to the assignee of the present invention in which a relay casing is divided by an insulative partition into a coil space for receiving an electromagnet and a switching space for receiving a contact assembly. While the relay of this application ensures effective insulation between the electromagnet and the contact assembly due to the employment of the insulative partition extending along the entire length of the electromagnet, there remains problems in that the electromagnet and the contact assembly are vertically arranged one above the other to result in increased height and that an armature extends across the electromagnet and the contact assembly at one longitudinal end of the relay casing to result in increased length of the relay. The above problems are less critical when the relay is designed to have a width as small as possible with little attention to the length and height of the relay. However, the problems attendant with the above relay construction becomes more critical when the relay is required to be manufactured at a minimum length and height for particular purposes.